Rotary Valves for Pneumatic Conveying Applications - CMT Inc.

220 Crompton St. Charlotte, NC 28273     +1 704-846-3737
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Rotary Valves

Rotary Valves for Pneumatic Conveying Applications

We provide a full range of heavy-duty valves including rotary airlock valves, diverter valves, weigh valves, slide gate valves, iris valves and maintenance gates. In addition, CMT provides butterfly, knife gates and orifice gates. Rotary Airlock Valves are used to introduce dry materials into a pressure conveying line “locking” the high-pressure (0-25 psig) air below the valve, thereby allowing material to be introduced into the conveying line.

A rotor, 6-12 vanes, delivers product on a continuous basis to the conveying line.   The rotor shaft is supported by two externally located bearings, which is a potential point of product leakage. Rotary Airlock Valves typically run at very slow speeds – 5 to 26 rpm.

Many users have a “dislike” for rotary  airlock valves, as they can be a source of high maintenance or unexpected breakdowns.  Although high pressure, abrasive applications are difficult for any supplier, many problems experienced by users are a result of the wrong features being utilized for an application.  Allow us to help solve your current problem by completely understanding your application and concerns.

Drop Thru Rotary Airlock Valves
The Drop Thru Rotary Airlock valve is our most popular unit and utilized in most applications. These valves are available with both round and square flanges, and Cast Iron or Stainless Steel construction.

Carolina Conveying’s rotary airlocks are a heavy duty design with robust castings, thick blade rotors with oversized shafts, outboard re-greaseable bearings, gland type shaft seals and high efficiency drive packages.


Open-end, closed-end, fixed blades, adjustable blades, beveled edges, scalloped pockets, reduced volume, quick release, Teflon coated, abrasion resistant tips, flexible rubber tips, and many more.

4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 24, 30 and 36 inch.
Side Entry Rotary Airlock Valves
The Side Entry Rotary Airlock Valve is used in applications where product shearing is a concern. The valve name derives from the offset inlet and outlet flanges, where the product enters the side of the rotor instead of the top.

On a normal valve, shearing takes place as the rotor rotates into the housing. When the rotor vanes meet the throat on a typical rotary airlock, this creates a pinched area where the product can shear and/or jam the valve.

With the side entry rotary airlock, the product is caught on the upswing of the rotor blades so that the product is constantly falling away from the shear point.

The rotor pockets also do not fill up as completely, additionally reducing the likelihood of shearing. Lastly, the throat has a V shape which helps push the product out of the way.
Easy Clean Rotary Airlock
The Easy Clean Rotary Airlock Valve is used in sanitary or food applications where the valve internals needs to be cleaned on a regular basis.

This valve is also useful in non-sanitary applications that require product change over, such as paint pigments.

The easy-clean rotary airlock valve features a quick-release rotor. With this design, the rotor can be removed without having to disconnect the drive package. Optional slide rails can support the rotor and end cover once it has been pulled apart.

- 6, 8, 10, 12 as standard. (Round or Square Flanges. Other sizes may also be accommodated.)

Scalloped rotor pockets, polished internals, wash down duty motor, stainless steel drive components and slide rails to support the rotor.
Blow Thru Rotary Airlock Valves
The Blow Thru Rotary Airlock Valve is used in pneumatic conveying applications, both positive pressure, and vacuum systems.

Instead of an outlet throat, the blow thru airlock has ports on the sides of the end covers that connect directly to the convey line pipe. The convey line air blows through the rotor pockets which is very efficient and cleans the pockets.

Since an outlet convey line adapter is not required, the blow thru airlock is also very compact and requires less space for installation.

The valve comes with adapters to match the line size, both standard schedule pipe and OD tubing are available.

A typical connection is via compression couplings, but adapters are also available with flanges and threaded couplings.
Standard Duty Rotary Airlock Valves
The Standard Duty Drop Thru Rotary Airlock is a less expensive alternative to the Heavy Duty Airlocks and is ideal for applications where a more robust valve is not required.

The Standard Duty Airlock is used in gravity flow or low-pressure differential applications such as on the bottom of a dust collector, surge hopper or silo, and are used for handling dry, free flowing, non-abrasive materials.

These units are precision machined for tight tolerances, as with all of our rotary airlocks, to ensure minimal air leakage.
Special Size Rotary Airlock Valves
Carolina Material Technologies offers several unique and different size airlocks, from rectangular units to larger bore bodies for increased capacity.

These units are precision machined for tight tolerances, as with all of our rotary airlocks, to ensure minimal air leakage.

If you have a special size requirement, check with us to see what options are available. Custom sizes can also be produced.

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220 Crompton St
Charlotte, NC 28273
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